Grain oriented electrical steel sheet

Abstract

A grain oriented electrical steel sheet includes the texture aligned with Goss orientation. In the grain oriented electrical steel sheet, when (α 1 β 1 γ 1 ) and (α 2 β 2 γ 2 ) represent deviation angles of crystal orientations measured at two measurement points which are adjacent on the sheet surface and which have an interval of 1 mm, the boundary condition BA is defined as |β 2 −β 1 |≥0.5°, and the boundary condition BB is defined as [(α 2 −α 1 ) 2 +(β 2 −β 1 ) 2 +(γ 2 −γ 1 ) 2 ] 1/2 ≥2.0°, the boundary which satisfies the boundary condition BA and which does not satisfy the boundary condition BB is included.

What is claimed is: 
     
       1. A grain oriented electrical steel sheet comprising, as a chemical composition, by mass %,
 2.0 to 7.0% of Si, 
 0 to 0.030% of Nb, 
 0 to 0.030% of V, 
 0 to 0.030% of Mo, 
 0 to 0.030% of Ta, 
 0 to 0.030% of W, 
 0 to 0.0050% of C, 
 0 to 1.0% of Mn, 
 0 to 0.0150% of S, 
 0 to 0.0150% of Se, 
 0 to 0.0650% of Al, 
 0 to 0.0050% of N, 
 0 to 0.40% of Cu, 
 0 to 0.010% of Bi, 
 0 to 0.080% of B, 
 0 to 0.50% of P, 
 0 to 0.0150% of Ti, 
 0 to 0.10% of Sn, 
 0 to 0.10% of Sb, 
 0 to 0.30% of Cr, 
 0 to 1.0% of Ni, and 
 a balance consisting of Fe and impurities, and 
 comprising a texture aligned with Goss orientation, characterized in that, 
 wherein α in unit of degrees is defined as a deviation angle from an ideal Goss orientation based on a rotation axis parallel to a normal direction Z, 
 β in unit of degrees is defined as a deviation angle from the ideal Goss orientation based on a rotation axis parallel to a transverse direction C, 
 γ in unit of degrees is defined as a deviation angle from the ideal Goss orientation based on a rotation axis parallel to a rolling direction L, 
 crystal orientations are measured on at least 500 measurement points with 1 mm intervals on a sheet surface, 
 using the α, the β, and the γ, α 1 , β 1 , and γ 1  in units of degrees represent deviation angles of crystal orientation measured at one measurement point and α 2 , β 2 , and γ 2  in units of degrees represent deviation angles of crystal orientation measured at the other measurement point in two measurement points which are adjacent on a sheet surface and which have an interval of 1 mm among the at least 500 measurement points, 
 a boundary condition BA is defined as |β 2 −β 1 |≥0.5°, and 
 a boundary condition BB is defined as [(α 2 −α 1 ) 2 +(β 2 −β 1 ) 2 +(γ 2 −γ 1 )] 1/2 ≥2.0°, 
 a boundary which satisfies the boundary condition BA and which does not satisfy the boundary condition BB is included, and 
 a value of dividing a number of a boundary which satisfies the boundary condition BA by a number of a boundary which satisfies the boundary condition BB is 1.10 or more. 
 
     
     
       2. The grain oriented electrical steel sheet according to  claim 1 , wherein
 a grain size RA L  is defined as an average grain size obtained based on the boundary condition BA in the rolling direction L, 
 a grain size RB L  is defined as an average grain size obtained based on the boundary condition BB in the rolling direction L, and 
 the grain size RA L  and the grain size RB L  satisfy 1.10≤RB L ÷RA L . 
 
     
     
       3. The grain oriented electrical steel sheet according to  claim 1 , wherein
 a grain size RA C  is defined as an average grain size obtained based on the boundary condition BA in the transverse direction C, 
 a grain size RB C  is defined as an average grain size obtained based on the boundary condition BB in the transverse direction C, and 
 the grain size RA C  and the grain size RB C  satisfy 1.10≤RB C ÷RA C . 
 
     
     
       4. The grain oriented electrical steel sheet according to  claim 1 , wherein
 a grain size RA L  is defined as an average grain size obtained based on the boundary condition BA in the rolling direction L, 
 a grain size RA C  is defined as an average grain size obtained based on the boundary condition BA in the transverse direction C, and 
 the grain size RA L  and the grain size RA C  satisfy 1.15≤RA C ÷RA L . 
 
     
     
       5. The grain oriented electrical steel sheet according to  claim 4 , wherein
 a grain size RB L  is defined as an average grain size obtained based on the boundary condition BB in the rolling direction L, 
 a grain size RB C  is defined as an average grain size obtained based on the boundary condition BB in the transverse direction C, and 
 the grain size RB L  and the grain size RB C  satisfy 1.50≤RB C ÷RB L . 
 
     
     
       6. The grain oriented electrical steel sheet according to  claim 4 , wherein
 a grain size RA L  is defined as an average grain size obtained based on the boundary condition BA in the rolling direction L, 
 a grain size RB L  is defined as an average grain size obtained based on the boundary condition BB in the rolling direction L, 
 a grain size RA C  is defined as an average grain size obtained based on the boundary condition BA in the transverse direction C, 
 a grain size RB C  is defined as an average grain size obtained based on the boundary condition BB in the transverse direction C, and 
 the grain size RA L , the grain size RA C , the grain size RB L , and the grain size RB C  satisfy (RB C ×RA L )÷(RB L ×RA C )<1.0. 
 
     
     
       7. The grain oriented electrical steel sheet according to  claim 5 , wherein
 a grain size RA L  is defined as an average grain size obtained based on the boundary condition BA in the rolling direction L, 
 a grain size RB L  is defined as an average grain size obtained based on the boundary condition BB in the rolling direction L, 
 a grain size RA C  is defined as an average grain size obtained based on the boundary condition BA in the transverse direction C, 
 a grain size RB C  is defined as an average grain size obtained based on the boundary condition BB in the transverse direction C, and 
 the grain size RA L , the grain size RA C , the grain size RB L , and the grain size RB C  satisfy (RB C ×RA L )÷(RB L ×RA C )<1.0. 
 
     
     
       8. The grain oriented electrical steel sheet according to  claim 1 , wherein
 a grain size RB L  is defined as an average grain size obtained based on the boundary condition BB in the rolling direction L, 
 a grain size RB C  is defined as an average grain size obtained based on the boundary condition BB in the transverse direction C, and 
 the grain size RB L  and the grain size RB C  are 22 mm or larger. 
 
     
     
       9. The grain oriented electrical steel sheet according to  claim 1 , wherein
 a grain size RA L  is defined as an average grain size obtained based on the boundary condition BA in the rolling direction L, 
 a grain size RA C  is defined as an average grain size obtained based on the boundary condition BA in the transverse direction C, and 
 the grain size RA L  is 30 mm or smaller and the grain size RA C  is 400 mm or smaller. 
 
     
     
       10. The grain oriented electrical steel sheet according to  claim 1 , wherein
 σ(|β|) which is a standard deviation of an absolute value of the deviation angle β is 0° to 1.70°. 
 
     
     
       11. The grain oriented electrical steel sheet according to  claim 1 , wherein
 a magnetic domain is refined by at least one of applying a local minute strain and forming a local groove. 
 
     
     
       12. The grain oriented electrical steel sheet according to  claim 1 , wherein
 an intermediate layer is arranged in contact with the grain oriented electrical steel sheet and 
 an insulation coating is arranged in contact with the intermediate layer. 
 
     
     
       13. The grain oriented electrical steel sheet according to  claim 12 , wherein
 the intermediate layer is a forsterite film with an average thickness of 1 to 3 μm. 
 
     
     
       14. The grain oriented electrical steel sheet according to  claim 12 , wherein
 the intermediate layer is an oxide layer with an average thickness of 2 to 500 nm. 
 
     
     
       15. The grain oriented electrical steel sheet according to  claim 1 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       16. The grain oriented electrical steel sheet according to  claim 2 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       17. The grain oriented electrical steel sheet according to  claim 3 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       18. The grain oriented electrical steel sheet according to  claim 4 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       19. The grain oriented electrical steel sheet according to  claim 5 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       20. The grain oriented electrical steel sheet according to  claim 6 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       21. The grain oriented electrical steel sheet according to  claim 7 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       22. The grain oriented electrical steel sheet according to  claim 8 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       23. The grain oriented electrical steel sheet according to  claim 9 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       24. The grain oriented electrical steel sheet according to  claim 10 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       25. The grain oriented electrical steel sheet according to  claim 11 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       26. The grain oriented electrical steel sheet according to  claim 12 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       27. The grain oriented electrical steel sheet according to  claim 13 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total. 
 
     
     
       28. The grain oriented electrical steel sheet according to  claim 14 , wherein
 the grain oriented electrical steel sheet has, as the chemical composition, at least one of Nb, V, Mo, Ta, and W, and 
 an amount thereof is 0.0030 to 0.030 mass % in total.